The present invention relates to a unit for a plasma atomizer device with a supply means for supplying a gas for generating a plasma, an atomizer means for atomizing a sample to be analyzed, an injection means for injecting the atomized sample into a plasma generated with the supplied gas, and a support means for holding the supply means, the atomizer means and the injection means.
Such units are known in the prior art. FIG. 6 illustrates such a unit according to the prior art. Said unit comprises a supply means 110 for supplying a gas for producing a plasma in a volume V. The supply means 110 normally consists of two small quartz glass tubes that are arranged such that the gas required for generating the plasma can be supplied on the one hand and a gas required for cooling the supply means 110 can be supplied on the other hand. Furthermore, there are provided an atomizer means 120 for atomizing a sample to be analyzed and an injection means 130 for injecting the atomized sample into a plasma generated with the supplied gas in the volume V. The supply means 110, the atomizer means 120 and the injection means 130 are mounted within a support means 100.
For the operation of the plasma atomizer device, the whole unit as illustrated in FIG. 6 is arranged by means of a fastening means 150 in a generator chamber which accommodates an RF generator for igniting and maintaining the plasma (not shown).
The unit which is known from the prior art has the drawback that the supply means 110, the atomizer means 120 and/or the injection means 130 can only be cleaned or replaced under great efforts. In particular, the generator chamber must be opened; the unit must be detached from the fastening means 150 and removed from the generator chamber.
Another drawback of the prior-art unit is that the supply means 110 and the injection means 130 are fixedly arranged relative to each other. This has the effect that a cleaning of the supply means 110 and of the injection means 130 is rendered more difficult.
It is therefore the object of the present invention to improve the unit according to the prior art in such a manner that the individual components are rendered more easily accessible so that the efforts for cleaning or replacing the supply means, the atomizer means and the injection means are considerably reduced.
This object is achieved by a unit of the above-described type which is characterized by the feature that the support means is connectable to a generator chamber wall of the atomizer device in such a manner that the supply means and the injection means are arranged inside the generator chamber.
Since the support means is connectable to the generator chamber wall, the whole unit can easily be inserted into the generator chamber wall and can easily be detached for cleaning or replacing the supply means, the atomizer means and the injection means. It is thus no longer necessary to open the generator chamber entirely and to detach the unit from the fastening means for cleaning or replacing the components.
According to a preferred development of the above-described unit the support means may be designed such that the atomizer means is arranged outside the generator chamber.
As a result, the atomizer means is freely accessible in the installed state of the supply means and in the installed state of the injection means and can be exchanged without removal of the supply means or the injection means for the purpose of cleaning or replacement.
According to a preferred development of the above-described units, the support means may comprise a holding means to which the supply means, the atomizer means and the injection means can be fastened in a removable manner, as well as a closing means which is arranged to be rotatable relative to the holding means and by means of which the unit can be fixed to the generator wall.
This measure makes it possible to insert the holding means with the attached supply means, atomizer means and injection means into the generator chamber wall to prevent rotation, and to fixedly connect the whole unit to the generator chamber wall just by rotating the closing means. Thus the holding means can be inserted with the components attached thereto into the generator chamber wall at a predefined angular position.
Advantageously, the closing means may comprise at least one pin that can be brought into engagement with a bayonet curve provided in the generator wall. The closing means can thereby be opened and closed in a particularly fast and easy manner.
The closing means can particularly be formed by two pins that are engageable with two bayonet curves provided in the generator wall. Thanks to the provision of two pins that engage into two bayonet curves, it is possible to achieve a uniform distribution of the forces arising during the closing operation.
Advantageously, each pin may be provided with a roller. This leads to a decrease in the frictional force between pin and bayonet curve, whereby the closing means can be operated with less force on the one hand and a closing of the pin/pins and the bayonet curve/bayonet curves is avoided on the other hand.
As an alternative to a bayonet closure, the connection means may also comprise a thread that is engageable with a thread provided in the generator wall.
According to a preferred development of all of the above-described units, a stop means may be provided for limiting a rotation of the closing means in the closing direction relative to the holding means.
Since the rotation of the closing means, which is e.g. provided with a bayonet or thread means, is limited, a fixedly defined. mounting depth of the supply means and the injection means can be achieved in the generator chamber, particularly with respect to the RF generator means. A defined mounting depth can in particular optimize the formation of the plasma. Moreover, manufacturing tolerances of the individual elements can be compensated for.
The stop means may advantageously comprise an element which can be fixed in different positions on the closing means or the holding means, as well as an element which is fixedly arranged at the side of the holding means or the closing means and which can be stopped on the fixable element.
Thus various mounting depths of the supply means and the injection means in the generator chamber can be adjusted in advance and set by rotating the closing means until abutment without the need for a repeated adjustment of the desired mounting depth.
Advantageously, the element which can be fixed in different positions onto the closing means or the holding means may be made annular and may rotatably be arranged relative to the closing means or the holding means in a non-fixed position and may comprise a first control curve along which the element fixedly arranged at the side of the holding means or the closing means can be guided and at the end of which said element can be stopped. Said measure results in a low-maintenance unit which can be produced in a particularly easy manner and thus at low costs. The annular element can here be moved by hand into the desired stop position.
According to a particularly advantageous development of said unit the annular element may comprise a second control curve, and an element, which is connected to the closing means or the holding means, may be provided that can be guided in a first position along the second control curve and, in a second position, clamps the annular element against the closing means or the holding means. A fixing mechanism for the stop means can be realized by said measure in a simple and thus also inexpensive and maintenance-friendly way.
This design can advantageously be developed such that at the end at which the element which is fixedly arranged at the side of the holding means or closing means can be stopped, the first control curve comprises a snap-in mechanism into which the element connected to the holding means or closing means can be snapped, so that the annular element can be guided relative to the closing means or the holding means into a position in which the annular element can be clamped against the closing means or the holding means.
It is possible with said features to realize a mechanism by which the stop means and thus the mounting depth can be adjusted by just moving the closing means relative to the holding means. To be more specific, it is thus no longer necessary to provide a mechanism for moving the stop means into the different positions for the different mounting depths outside the closing means and the holding means. Furthermore, it can be ensured in the case of said design that after the removal of the unit for cleaning purposes or for replacing components the previously set mounting depth can exactly be adjusted again to the desired position after the cleaning process has been finished or after individual components have been replaced.
Said mechanism can be operated as follows, in particular in order to reproduce an adjusted mounting depth. (For the sake of simplicity it will be assumed in the following that the element which is guidable along the first control curve is fixedly connected to the holding means and the element which is guidable in its first position along the second control curve is connected to the closing means and, in its second position, clamps the annular element against the closing means.)
After the desired mounting depth has been set, the annular element which is fixed onto the closing means is released by the measure that the element which clamps the annular element to the closing means is moved into its first position. The holding element will then be rotated in the closing direction until the maximum mounting depth has been reached at which the element secured at the side of the holding means snaps into the snap-in means at the end of the first control curve. The annular element is thereby temporarily connected to the closing means. A rotation of the closing means into the original position will now have the effect that the annular element remains fixed relative to the holding means and assumes a stop position corresponding to the desired mounting depth relative to the closing means. A rotation of the closing means with respect to the opening direction for removing the unit will now have the effect that the element disengages from the snap-in mechanism and can be removed from the generator chamber wall in the end. When the unit is now inserted again and the closing means is rotated in the closing direction, said rotation will be limited by the element at the side of the holding means snapping into the snap-in means, i.e. by the originally set position corresponding to the mounting depth.
According to a preferred alternative to the above-described units the support means may comprise a means which can be engaged by at least one clip provided at the side of the generator wall. The unit can thereby be removed from and secured to the generator chamber wall very rapidly by opening or closing the clip provided at the side of the generator wall.
Preferably, the support means may comprise a means that is engagable by two clips provided at the side of the generator wall. A symmetrical distribution of the holding force over the unit is ensured by said measure.
According to an advantageous development of all of the previously described units the injection means may be provided on the support means to be fixable from the side of the support means that is facing away from the generator chamber. It is thereby possible to remove the injection means independently of the support means and the supply means for cleaning purposes or for the purpose of replacement.
A particularly advantageous development consists in that the support means is provided with a locking mechanism by which the injection means can be locked to the support means. Such a measure can implement a simple, but nevertheless operationally reliable, fastening means, which in addition can be operated without wasting time.
Advantageously, the locking mechanism may comprise a slide means which is displaceable in a displacement direction extending at an angle relative to the longitudinal axis of the injection means, the slide means comprising an opening through which the injection means can be guided, and the slide means being preloaded relative to the support means in such a manner that in the installed state of the injection means said means is clamped in the displacement direction against the support means.
Expediently, but not limited to such a design, the slide means may be displaceable in a displacement direction extending in a direction perpendicular to the longitudinal axis of the injection means.
According to a further advantageous development of all of the above-described units, the support means may comprise a clip means for fastening the atomizer means to the support means. Such a clip means permits a very fast replacement of the atomizer means, without the support means with the supply means and the injection means having to be removed from the generator wall.
Advantageously, the clip means may here be designed such that the atomizer means can be secured in a first position to the support means and fixed in a second position to the support means.
The clip means is expediently shaped in the form of a bow whose shape is adapted to the cross section of the atomizer chamber of the atomizer means. An easy operability is thereby ensured on the one hand and a perfect function of the fastening means on the other hand.
According to a preferred development of the units with the clip means, the support means may comprise an ejection means for facilitating a removal of the atomizer means from the support means. Such an ejection means is of particular advantage during prolonged operation of the unit because in such a case the sealing rings often get stuck between atomizer chamber and holding means, and such an ejection means considerably simplifies the removal in the case of seals that have got stuck.
Expediently, in units provided with both an ejection means and a clip means, the two means may be made integral. The constructional efforts for the unit are thereby reduced, resulting in reduced production costs. Moreover, the atomizer chamber can be removed with a handle, i.e. after the complete opening of the clip means.